Tag Archives: brain

While the title of this article may at first seem implausible (and somewhat scary), a new scientific study seems to show that an inborn preference for junk food is not only possible – it may be affecting more of us than ever could have possibly been imagined. For the first time in history, researchers for Obesity Society have identified two genetic variants, which help to change how the brain responds to high-calorie foods.12 While this is potentially terrible news for those of us who struggle to resist highly processed and manufactured foods – it also means there is possibly a way to stop this genetic variant from controlling our dietary choices. This could include changing how the brain processes junk food, changing how much people crave these foods, and even altering the brain’s dopamine system. There are even more potential treatments using this new information – including using gut hormones to act on dopamine brain cells.

To delve into further detail, researchers specifically found that two genetic variants – FTO and DRD2 – influenced brain activity related to the reward system. This occurred when subjects simply looked at pictures of high-calorie foods. As I’ve written previously, this is far from the first time neuroscience (or other scientific studies) have shown that some of our brains respond differently, to rewarding foods.34567891011 In early 2014, for example, a study was published which showed that not only did some people crave chocolate (while others did not) – but that there was literally different brain activity, in the two groups.12

In another, similar study, researchers found that by altering dopamine receptors (specifically D2 receptors) – they could cure binge eating.13 Unfortunately for us, that ground breaking study was done on rats – not humans. However, this is further evidence that our brain plays a fundamental role in overeating and cravings. In fact, it may be the excess stimulation of the nucleus accumbens (the ‘pleasure center’ of the brain) from junk food, which leads to obesity.14151617181920

How does this relate to our current world? Well, 70% of the United States is overweight, with 30% of us now being obese.21 What accounts for all these extra pounds? Certainly, as shown by research from Yale scientists, a hyper-stimulatory environment and excess advertisement of junk food – is a large part of the problem.222324 But this data is compounded by other research, which shows that extended access to high-fat and high-sugar food, results in behavioral and physiological changes – which are similar to those caused by illegal drugs.25[26] While a large portion of these corresponding studies were conducted on rats, this does not mean that the results will not translate to humans. Like many areas of scientific research, we simply need more data.

As I’ve covered previously, the neurobiology of sugar addiction is fascinating as well.2728 The brain is bombarded with an overwhelming amount of chemicals and reward, when you consume junk food.29303132 Over time, this leads to a higher quantity of junk food needing to be consumed, to achieve the same rewarding effect.333435 So even for those of us who are not genetically susceptible to the temptations of junk food, we can alter our brain’s preferences and reward receptors, to become just as likely to crave it.3637383940

The good side of all this bad news? Your brain can also be positively impacted by food.414243444546 A Paleo diet, which is full of nutrient dense foods, will help keep you satiated, and keep your brain from craving high sugar, nutritionally empty choices. Be sure to load your plate with wild-caught fish (high in brain-friendly omega-3 fatty acids), healthy fats (like avocados) and complete sources of protein (like grass fed beef). You may indeed be hardwired for junk food – but that doesn’t mean you have to give in to temptation. Adopting a Paleo diet is associated with many different health benefits – many of which work to counteract the negative effects of junk food.47484950 What this means, is that you can improve your health drastically, by simply changing what’s on your plate. Start eating a Paleo diet today, and watch your health soar!

I’ve previously discussed the variety of positive neuronal changes that occur when consuming a healthier, Paleo Diet. This is especially true when you are moving away from a Western diet, filled with inflammatory seed oils, empty calories, and lots of sugar.1,2 When consuming these foods, your brain literally reprograms itself, to come to crave and long after its next “fix.”3,4 This is where changing your diet can not only help to change your body, but also your mind.5,6

Take for example, the Nrf2 transcription factor. Nrf2 is a master regulator of intracellular redox homeostasis.7 Some research has shown that a ketogenic diet may activate the Nrf2 pathway via redox signaling, leading to chronic cellular adaptation, induction of protective proteins, and improvement of the mitochondrial redox state.8 Other research has shown that dietary flavonoids (mainly vegetables and fruits) are neuroprotective via proteins related to Nrf2.9 Nrf2, or nuclear factor erythroid 2-related factor 2, is critical for neuronal protection, through the induction of various cytoprotective genes.10

With this information in hand (or should I say, in your head) it starts to become clearer how making a simple change in your diet, can have many protective effects, especially when trying to avoid Alzheimer’s, or other debilitating neurological conditions.11 Many chronic diseases are underpinned by chronic inflammation, and yes, this extends to inflammation of the brain, as well.12,13 As researchers have stated, the Keap1/Nrf2/ARE pathway plays a major role in health resilience and can be made more robust and responsive by certain dietary factors.14

With the damaging amount of free radicals produced by today’s high stress, low sleep and low nutrient lifestyles, it is time to take a serious look at just how much damage you are doing to your brain.15,16 Do you think it is just a mere coincidence that the New England Journal of Medicine correlated higher average blood sugar (which occurs from consuming a high sugar diet) with an increased risk for dementia?17 I don’t. Our rates of crippling neurological disease have risen exponentially, as, simultaneously, has the rate of type 2 diabetes, which is obtained from, you guessed it, a high sugar diet.18

But it is not simply removing sugar that is the answer to all of our problems. It is also what foods and calories you are consuming, instead of the sugary breakfast cereals, pastries, and donuts. Vegetables have many beneficial compounds, which have been shown to help provide protection against neurological breakdown, and even enhance cell-to-cell signaling.19 This makes perfect sense given the many poor quality foods that can cause an increase in inflammatory chemical production.20 So, the basic hypothesis is simple: remove the foods causing the inflammation and higher rate of glycation (aging process), and replace them with foods that enhance neuronal signaling, and protect your brain from damage.21

One element not yet discussed, is BDNF, or brain-derived neurotrophic factor.22 A 2002 neuroscience study sums up this factor, and more specifically, how a poor diet can negatively affect your brain. Researchers concluded that a high-fat, refined sugar diet reduces hippocampal brain-derived neurotrophic factor, neuronal plasticity, and learning.23 Unfortunately, the term “high fat,” continues to prevail in the scientific community, when researchers really mean trans fat, poor quality fat, and/or high fat plus high sugar. Nonetheless, this study easily conveys the idea that a poor diet will immediately cause problems in your hippocampus, your ability to learn, and how the brain reorganizes neuronal pathways in the brain. In a word: Bad.

BDNF importance stems from not only helping to support the survival of existing neurons, but encouraging the growth of new neurons and synapses.24 Yes, this means that it, quite literally, can help you get smarter.25 So, if you’re consuming a poor diet, you will likely not be able to improve your intelligence at the same rate as you would, when consuming a healthier, Paleo Diet. BDNF is just one of the many factors that play into the neurological role of consuming healthy fats, high quality sources of protein and lots of vegetables, all key tenets of a Paleo Diet.

Let’s talk about leptin resistance and what impact this condition has on your brain.26 When consuming a poor diet, you are very likely to develop insulin resistance.27 Accompanying that, is usually leptin resistance.28 Leptin is your body’s way of telling your brain that you are full, and you do not need to eat any more food.29 Those born with a leptin deficiency, almost immediately become obese, because their brain simply cannot realize they have consumed enough calories.30

But leptin resistance, rather than leptin deficiency, means you are now resistant to the body’s way of telling your brain to stop eating.31 This leads to a whole host of problems, the least of which, is over consumption and the resulting weight gain.32 Researchers have found that chronically elevated leptin decreases hypothalamic leptin receptor expression and protein levels and impairs leptin signaling.33 This is only the first step in the vicious cycle of weight gain via leptin resistance.34 Since hypothalamic leptin receptor expression has been decreased, your brain actually changes from consuming a poor diet.35,36,37

Many people are unaware of all the pathways and details that come from simply changing the food that is on their plate. But the many crucial scientific changes that occur, silently, but steadily, are what really lead to obesity and disease.38,39 Becoming aware of them, and changing what you put in your mouth, is perhaps the single most important thing you can do, to get healthier and to save yourself from a lifetime of chronic disease and unhappiness.40,41 A Paleo Diet is brain-friendly, and will be one of the biggest changes you make, to become smarter, happier, leaner, and disease-free!

REFERENCES

[2] Poti JM, Duffey KJ, Popkin BM. The association of fast food consumption with poor dietary outcomes and obesity among children: is it the fast food or the remainder of the diet?. Am J Clin Nutr. 2014;99(1):162-71.

With the plethora of benefits supported by scientific evidence,1 Gluten-free diets have been gaining in popularity in recent years.2 Studies range from gastrointestinal symptom improvement,3 to possible correlations with autism,4 and diabetes.5 However, there may not be a more fascinating area of gluten study than how the protein composite can be related to cognitive function.6 One study shows large changes in brain tissue, specifically, white matter, in those who are sensitive to gluten.7

Why is this an important discovery? White matter is actively involved in neurogenesis, or “the growth of new neurons.”8, 9, 10 If gluten is possibly disrupting this process, like chemotherapy has been studied to do,11 then its effects may not be just temporary and transient. Instead they may be both long lasting and potentially damaging.12

Stress, sleep disruption, exercise and inflammation have all been linked with regulating hippocampal neurogenesis and implicated in the pathophysiology of mood disorders.13 But can gluten be linked to mood disorders? The science says yes.14

Many reports evidence unexpected resolution of long-term schizophrenic symptoms, when eliminating gluten from the diet.15 Interestingly, one study of Pacific Islanders who consumed almost no grains (or dairy) showed that only 2 in 65,000 subjects presented with overtly psychotic cases of schizophrenia.16, 17 However, since there are oftentimes confounding variables in these studies, it is not yet mechanistically clear on what may be causing remission of symptoms.18

In regards to cognitive function, as far back as 2004, scientists have shown improvements in the frontal region of the brain, in subjects consuming a gluten-free diet.19 Other research shows gluten’s effects are clearly not limited to gastrointestinal issues alone.20

To whom does this apply21 and how exactly does gluten cause cognitive impairment? Definitively, we can seem to say that removing gluten from the diet improves cognitive functioning in many individuals.22, 23 Gluten elicits an adaptive Th1-mediated immune response in individuals carrying HLA-DQ2 or HLA-DQ8 genes.24

The “foggy brain” symptoms, as reported by non-celiac disease subjects, are intriguing. In these subjects, we see an up-regulation of claudin-4, which is associated with an increased expression of toll-like receptor-2 and a significant reduction of the T-regulatory cell marker FoxP3.25 This is part of why an innate immune system response seems to be involved in these subjects, rather than an adaptive immune system response.

Gluten sensitivity as a neurological illness

However, individuals diagnosed with celiac disease, α-amylase/trypsin inhibitors (ATIs) are strong activators of innate immune system responses in macrophages, monocytes and dendritic cells, via toll-like receptor-4.26 Despite these details, however, we cannot yet definitively say that gluten causes cognitive impairment,27, 28 no matter how likely it may seem in the scientific literature.

Brain MRI of a patient with gluten ataxia showing rapid onset of cerebellar atrophy over a period of 15 months before the diagnosis of gluten ataxia.

The distinction is very important. A much-publicized study29 from early 2014 suggested it might not be gluten itself that causes issues, but instead it may agglutinins, FODMAPs, prodynorphins, deamidated gliadin and/or gliadorphins.

These findings illustrate more studies need to be done in order to show, mechanistically, what is causing physiologic disruptions, changes in white matter. Furthermore, research may determine distinct populations that should avoid gluten, if indeed the protein composite is causing these issues.

“Early diagnosis and removal of the trigger factor, by the introduction of a gluten-free diet, is a promising therapeutic intervention,” said researchers in a study published in the Journal of Neurology.30 A promising intervention – that needs much more research.31

I do not dismiss anecdotal improvements seen in individuals adopting gluten-free diets, such as the Paleo Diet. And with that said, we need instead maintain scientific rigor and provide the best, most accurate, recommendations possible.

The negative effects of gluten and other gluten-like compounds have been well-documented for many years.32, 33, 34, 35 Just because a specific mechanism for neurologic dysfunction hasn’t yet been identified – doesn’t mean gluten is doing anyone any favors.36, 37

We must also remember that although the human genome has remained primarily unchanged since the agricultural revolution 10,000 years ago, our diet and lifestyle have become progressively more divergent from those of our ancient ancestors.38, 39 A Paleo Diet still provides the best defense against neurologic impairment, as well as providing favorable changes in risk factors, such as weight, waist circumference, C-reactive protein, glycated haemoglobin (HbAlc), blood pressure, glucose tolerance, insulin secretion, insulin sensitivity and lipid profiles.40

I was hoping I could induce you to correct a statement made about your work in a recent post in The Atlantic. It’s by a senior editor, a medical doctor, James Hamblin, who’s doing . In it he quotes David Katz of Yale, commenting about the paleolithic diet and your work.

I thought perhaps you could take a little time to set both Hamblin and maybe even Katz right. The key section:

“Of course,” Katz added, “Everything about the Paleolithic Era is subject to debate. Most of us don’t know what we had for breakfast yesterday, let alone what people were doing 100,000 years ago. Yeah, I’ve read the same thing that the average life expectancy was between 20 and 40 and, consequently, the diseases of old age didn’t happen because old age didn’t happen. There’s nothing about their diet that we know to be protective against things like Alzheimer’s. That’s just silly.”

Perlmutter has estimated that the Stone Age diet was 75 percent fat, a claim Katz finds “wildly preposterous.” Anthropological research, he pointed out the work of , suggests that in the age before cooking oil, humans ate mostly plants with a scattering of seeds and nuts. “Virtually nothing in the natural world is that concentrated of a fat source, except maybe for the brain. Maybe if they just ate the brains of animals? They didn’t have oil. They only started adding oil to the diet after the Dawn of Agriculture. What the hell could they possibly have eaten that would be that fatty?'”

This kind of journalism is bad enough when they get the facts vaguely right and just spin them to fit their biases. When they butcher the facts, too, it deserves correcting.

All the best,

Gary Taubes

Gary Taubes is the author of , Nobel Dreams (1987), Bad Science: The Short Life and Weird Times of Cold Fusion (1993), and Good Calories, Bad Calories (2007), which is titled The Diet Delusion in the UK. He has won the Science in Society Award of the National Association of Science Writers three times and was awarded an MIT Knight Science Journalism Fellowship. Taubes studied applied physics at Harvard and aerospace engineering at Stanford (MS, 1978). Taubes has written numerous articles for Discover, Science and other magazines. Originally focusing on physics issues, his interests have more recently turned to medicine and nutrition.

Dr. Cordain’s Response:

Hi Gary,

Good to hear from you. Thanks for forwarding me the by James Hamblin, MD. on Perlmutter’s Grain Brain. I came away with a number of impressions:

1. Both Katz and Perlmutter acknowledge the underlying, evolutionary basis for human nutrition.

2. Scientists involved in gluten research and Paleo Diets (including myself) were not directly interviewed in this article. This omission likely fuels Hamblin’s perspective and does not provide equal input for both sides of the argument.

3. I was not interviewed for this article and the quote you cite below is not mine, but rather appears to be David Katz’s interpretation of our work. The quote is erroneous as well as being just flat out wrong. Our group has repeatedly analyzed the composition and macronutrient content of historically studied hunter gatherer diets.1-7 since the origins of our genus Homo. To correct whomever wrote the erroneous quote below, regardless of whether fat comes from either plant or animal food sources, it contains identical caloric densities (9 kcal/g). In the typical hunter gatherer diet, animal fat would have generally exceeded plant fat on an average daily basis.

Brain contains virtually no fat, but rather is comprised primarily of fatty acids bound to the phospholipid fraction. A fat (triglyceride) is also technically called an acylglycerol (a glycerol molecule bound to a fatty acid [acyl group] via an ester bond). Brain contains little or no acylglycerol, but rather structural fatty acids found not in the triglyceride fraction, but in the phospholipids fraction. There is no doubt that brain, marrow and other fatty (and ) portions of wild animal carcasses would have been preferred by our hunter gatherer ancestors over lean meats.

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